Study medication was provided at week 0 and, therefore, week 1 contains those individuals who had received 1 or more weeks of double-blind treatment. Weekly mean proportion of cocaine nonuse days was analyzed (A) without imputing missing data and (B) imputing missing data using baseline values. Each symbol represents the mean proportion of cocaine nonuse days for each study week, and the error bars indicate standard error (SEM). Participants were allocated to treatment groups at the end of the 2-week baseline period.